1. Field of the Invention
The present invention relates to a method for producing tertiary alcohols.
2. Related Art
Tertiary butyl alcohol (TBA) and tertiary amyl alcohol (TAA) have classically been synthesized in the past by reaction of sulfuric acid with the corresponding olefin to form the sulfate followed by hydrolysis. The use of sulfuric acid requires reconstitution of dilute acid by-product and the process is energy inefficient and corrosive. Recycle of the excess water, which contains some TBA, causes corrosion unless it is specially treated. Most of the TBA produced at present, however, is a by-product from the OXIRANE process for propylene oxide. In that process isobutane is oxidized to tho hydroperoxide which is then catalytically reacted with propylene to produce propylene oxide and TBA.
More recently TBA has been produced using an acid ion exchange resin to react isobutylene in a mixed C4 stream with water. See, for example U.S. Pat. Nos. 4,087,471 and 4,100,220. The resin catalyzed process is highly exothermic and is limited to equilibrium conversions, requiring separation of the TBA from excess water. U.S. Pat. No. 4,087,471 is specifically directed to the cooling aspect of the fixed bed reactor. Additionally, oligomers are produced as by-products, their production rate being determined by the amount of excess water used.
Recently a new method of carrying out catalytic reactions has been developed, wherein the components of the reaction system are concurrently separable by distillation, using the catalyst structures as the distillation structures, the method being commonly referred to as Catalytic Distillation. Such systems are described variously in U.S. Pat. Nos. 4,215,011; 4,232,177; 4,242,530; 4,302,356; 4,307,254; 4,336,407; 4,439,350; 4,443,559; and 4,482,775 commonly assigned herewith.
Briefly, a preferred and commercial catalyst structure described in the above patents comprises a cloth belt with a plurality of pockets spaced along the belt and containing particulate catalyst material, said cloth belt being wound in a helix about a spacing material such as stainless steel knitted mesh. These units are then disposed in the distillation column reactor. In addition, commonly assigned U.S. Pat. Nos. 4,443,559 and 4,250,052 disclose a variety of catalyst structures for this use and are incorporated herein.